For those of you who like to keep your hands on the keyboard…

Control-tab will cycle to the next tab to the right (and wrap at the end).

Page-up and Page-down keys can be used to move to adjacent tabs in either direction (again, wrapping is in effect). Control-page-up (control-fn-page-up on laptop keyboards) moves left. Control-page-down (control-fn-page-down) moves right.